Sub perfecto()
        Dim ms As String = "Los perfectos numeros son"
        Dim i, b, sumdiv As Integer

        sumdiv = 0
        ListBox1.Items.Clear()

        For b = 0 To c - 1
            n = Int(grid1.Rows(b).Cells(0).Value)
            sumdiv = 0
            For i = 1 To n - 1 'evaluamos el numero y sus divisores
                If (n Mod i) = 0 Then
                    sumdiv = sumdiv + i
                End If
            Next
            If sumdiv = n Then
                With ListBox1
                    .Items.Add(n)

                End With


            End If
        Next

    End Sub